Undubble MSG_MIN & MSG MAX

add ```^ !(n_ENABLE_ON)``` for each stepper

In-line comments and escaping fixed by foosel

  * "G1 X1 ; test" was not executing "G1 X1" due to never leaving comment mode.
  * "M117 Hello \;)" printed "Hello \" to the display due to not replacing serial_char properly.

Tested with the following commands:
    * M117 Hello ; test => displays "Hello" on display, ignores "test"
    * G1 X1 ; foo => moves 1mm in X, ignores "foo"
    * ; test => completely ignored, not even acknowledged
    * M117 Hello \;) => displays "Hello ;)" on display
    * M117 Hello \\;) => displays "Hello \" on display, ignores ")"

dev pull

Latest upstream changes

Gcode handlers to inline functions

Enhanced G29

Latest upstream changes

Fix autoretract

Autoretract was broken, looks like it was overlooked when the retracted flag was updated for multi extruders.

Sync with upstream

Add support for solenoid articulated extruders

- Setting boundaries based on configured limits, contrasting with G28
(which forgets these limits?)

Cleanup rotary encoder encrot* defines

- Adapted “Enhanced G29” code referred to in #1499 and posted at
[3dprintboard.com](http://3dprintboard.com/showthread.php?3105-Auto_Bed_
Leveling-Enhanced-G29-command)
- Compatible with current G29 while adding some new arguments
  - `V` sets the verbose level for serial out
  - `T` (or `V` > 2) send a Topology report to serial out
  - `E` works the same way as before
  - `P` works as before (source used `n` or `U`/`u`)
  - `L`, `R`, `B`, `F` work as before
- Still needs sanity checking for `LRBF`

The X_Axis could not home to min while Y_Max endstop was trigged.

Cleanup of cardreader.*

- Apply standards to cardreader.*
- Fix minor issues with cardreader.cpp
- Apply standards to some other stale regions

The encrot values are used in only one place, and don’t vary, so remove
redundant references.

Latest upstream changes

This reverts commit fb75a9272d.

Cleanup of temperature code